A mayenite type compound is a compound derived from a cement mineral produced in Mayen in Germany and is an oxide ion clathrate aluminosilicate having a representative crystal skeleton of 12CaO.7Al2O3 (hereinafter, sometimes denoted by “C12A7”).
With respect to conductive mayenite, PTL 1 describes a method for producing conductive mayenite by treating a mayenite type compound with a plasma generated from a rare gas.
Further, PTL 2 describes that conductive mayenite (Ca24Al28O644+.4e−) is produced by irradiating hydrogen-substituted mayenite (Ca24Al28O644+.4H−) obtained by substituting free oxygen of mayenite (Ca24Al28O644+.2O2−) with hydrogen with ultraviolet light.